1. Field of the Invention
The present invention relates to a liquid crystal display device with a touch panel.
2. Description of the Related Art
A touch panel that is disposed so as to overlap on a display screen of an information and communication terminal such as a computer is widely used as an input device. A liquid crystal display device which is typically spread as a display device is a device that displays an image by changing an alignment of liquid crystal composition confined between two substrates, a thin film transistor substrate (hereinafter, referred to as a TFT substrate) and a color filter substrate by a change in an electric field, and then, controlling the degree of light transmission passing through a liquid crystal panel. Among the liquid crystal display devices, in an in plane switching (IPS) type in which both of a pixel electrode and a common electrode are disposed on the TFT substrate side, a so-called transverse electric field is formed, and a display with a wide viewing angle is realized.
The touch panel is an input device that recognizes coordinates on the panel touched by user's fingers, which causes a processing device to perform processing. As types of the touch panels, a resistance film type in which a change of resistance value at the touched point is detected, a light sensor type in which a change of a light amount at the point where the light is blocked by the touching is detected, and an electrostatic capacitance coupling type in which a change of capacitance is detected, are known. The electrostatic capacitance coupling type is widely used due to the point that the display image quality does not deteriorate by a high transmittance of the panel, and the point that there is no contact with other electrodes, which results in a high durability.
In recent years, in regards to requests to make an information and communication terminal small and thin, the liquid crystal display device with a touch panel also is required to be made thin. In JP 2009-244958A, in the IPS typed liquid crystal display device, a thinner liquid crystal display device with a touch panel by using the common electrode of the liquid crystal display device as a drive electrode of the touch panel, is disclosed.